C++ does not allow zero-sized unions - they end up being of size 1-byte, which leads to C/C++ compatibility issues, flagged by the compiler.
lib/node/rte_node_mbuf_dynfield.h:78:2: error: union has size 0 in C, size 1 in C++ [-Werror,-Wextern-c-compat] 78 | union { | ^ 1 error generated. Fix the error by omitting the persistent_data field when it is zero-sized, since it's unusable. Any app using the field must already specify a size for the persistent data. Fixes: 746e8736da70 ("node: add global mbuf dynfield") Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> --- lib/node/rte_node_mbuf_dynfield.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/lib/node/rte_node_mbuf_dynfield.h b/lib/node/rte_node_mbuf_dynfield.h index b77fdbb94f..09254c585a 100644 --- a/lib/node/rte_node_mbuf_dynfield.h +++ b/lib/node/rte_node_mbuf_dynfield.h @@ -69,6 +69,7 @@ typedef struct rte_node_mbuf_overload_fields { * 2. Overloadable fields: Fields which can be repurposed by two adjacent nodes. */ typedef struct rte_node_mbuf_dynfield { +#if RTE_NODE_MBUF_PERSISTENT_FIELDS_SIZE > 0 /** * Persistent mbuf region across nodes in graph walk * @@ -78,6 +79,7 @@ typedef struct rte_node_mbuf_dynfield { union { uint8_t persistent_data[RTE_NODE_MBUF_PERSISTENT_FIELDS_SIZE]; }; +#endif /** * Overloadable mbuf fields across graph walk. Fields which can change. * -- 2.48.1